Large terrestrial (330mm squared by 450mm long) tank is 4mm glass.
The last time I priced glass for the above tank it was going to cost me R120 for 4mm glass, cut and erased.

(It not exact weight though as there is no lids or doors included in that weight.)

Large terrestrial tank specs:
Glass Weight of tank = 8kg (with out substrate, ornaments and lid)
Glass Area = 0.66 Meter²
Glass Thickness = 4mm glass
Aquarium Volume = 49 liters

With the Arboreal tank 3mm is fine as the tank is basically a box and there is not much pressure on the sides of the glass
But if you got the cash then 4mm is a much safer option and does not cost that much more than the 3mm glass, just a bit heavier though.

If you are building front opening doors, then 4 mm glass is a must.

Arboreal tank specs: (3mm glass)
Glass Weight of tank = 4kg (with out substrate, ornaments and lids/doors)
Glass Area = 0.46 Meter²
Glass Thickness = 4mm glass
Aquarium Volume = 25 liters

Arboreal tank specs: (4mm glass)
Glass Weight of tank = 6kg (with out substrate, ornaments and lids/doors)
Glass Area = 0.46 Meter²
Glass Thickness = 4mm glass
Aquarium Volume = 25 liters

Cabinet specs:
16mm pressed wood.
Hieght = 2370mm
Length =1552mm
Width = 280mm
Support = @ 752mm (middle)
Spacing of the shelving is 450mm in height the 50mm is basically a big air vent.

I have upright support in the middle of the cabinet at 752mm, as pressed wood can only go up to 700 to 750mm then it start bowing after that.
In future I will rather use super wood as it is far stronger and it is a R100 difference in price.

I will be adding extra support, in the front and back under every shelf and then I will be putting support on the ends and against the middle support with a extra support in the middle of the 752mm at 710mm.

I have another cabinet that is almost the same size, it is 800mm wide and I removed a middle support from the one shelf and it is still straight. and it has a couple of tanks on the top shelf.

I have decided to over kill and rather over design it and make sure it is perfect.
30 tanks @ 10kgs a tank is pretty dam heavy.
300kg!! :ohmy: :swaet: noob :pinch: shocked

Thanks! That's way more detail than I had anticipated.
I use laminated wood - don't know if it is super or pressed or pressed superwood. Basically planks supported by threaded rods uprights. Free span is 850mm and I notice 5mm center sag with the one 4mm large arboreal and a bunch of plastic pasta containers.

My grandfather use to swear by laminated wood, when he stayed in Sabie most things he built was out of laminated wood.

Pressed wood is the same a chipboard, just get different standards of the stuff.

You can just put a support in the front and back of the shelf,something like 50 X 25 piece of timber glue and screw together, that should be strong enough to support your shelves with the weight.
Or you can do a canter lever design, where you place a piece of wood in the middle of the shelve attached to a piece of wood running the the full height of you cabinet with a small piece of wood in the front.
That way you still have your space to pack tanks and enclosures.